Heat the milk in a small saucepan over medium-low heat until steaming.
Stop at about 150 degrees F, before it boils.
Whisk vigorously or use a frother until the milk is silky and foamy.
Pour the milk into the mug, holding back the foam with a spoon.
Spoon the foam over the top and serve hot.
Notes
Add syrup to the cup first so it blends. Do not boil the milk. For an iced version, pour syrup over ice, add cold milk and espresso, and stir. Use 1 tablespoon of syrup for a lighter sweetness.